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1. [Amps] Longshot - looking for 8873 (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Fri, 6 Apr 2012 10:27:25 -0400
Anyone know of a working 8873 available anywhere? Resurrecting an SB-230 for a local ARES/RACES group and haven't been able to find one... Thanks. -- Jeff WN3A _______________________________________
/archives//html/Amps/2012-04/msg00071.html (6,594 bytes)

2. Re: [Amps] Tubes vs. Solid State (was) Expert Amps 2K-FA: AnyOpinions ? (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Mon, 30 Apr 2012 10:19:46 -0400
In solid state broadcast transmitters, there is always APC (automatic power control). The exciter or IPA power output is varied dynamically, usually under microprocessor control, to keep the final T
/archives//html/Amps/2012-04/msg00287.html (11,381 bytes)

3. Re: [Amps] Tubes vs. Solid State (was) Expert Amps2K-FA:AnyOpinions ? (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Mon, 30 Apr 2012 12:19:14 -0400
Ahhh...now there's the rub... Liquid cooling has become quite mainstream. Heck, even liquid cooling overclocked PC CPU's and GPU's isn't uncommon. I can walk into the local MicroCenter and buy every
/archives//html/Amps/2012-04/msg00294.html (10,186 bytes)

4. Re: [Amps] Tubes vs. Solid State (was) Expert Amps 2K-FA: Any Opinions ? (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Mon, 30 Apr 2012 13:34:54 -0400
I've had a Palstar HF-Auto for about six months now, and so far, no arcin' or sparkin' at the legal limit into some fairly ugly loads, particularly on 75/80m where I have an inverted vee cut for the
/archives//html/Amps/2012-04/msg00300.html (13,265 bytes)

5. Re: [Amps] MW-1A (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Tue, 1 May 2012 20:41:51 -0400
In contrast, I was running 24/7 trying to keep three of them on the air... _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/l
/archives//html/Amps/2012-05/msg00042.html (6,910 bytes)

6. Re: [Amps] Mismatch loss (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Thu, 3 May 2012 21:21:45 -0400
That sure sounds Maxwellian to me (Walt, not James Clerk :-) -- Jeff WN3A _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/lis
/archives//html/Amps/2012-05/msg00143.html (15,367 bytes)

7. Re: [Amps] Dummy Load Blues (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Fri, 15 Jun 2012 14:25:21 -0400
I usually go by taste. Seriously, the most-basic test is that PCB oils are heavier than water, while mineral oil is lighter than water. A couple of drops of of the subject oil in a cup of water woul
/archives//html/Amps/2012-06/msg00155.html (9,272 bytes)

8. Re: [Amps] RF insulating materials - engineered plastics (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Tue, 28 Aug 2012 11:18:02 -0400
Minor correction - you used diameter of the puck instead of the radius when calculating the area. C = 2.1 * 0.2248 * (1.5/2)^2 * pi / 0.75 = 1.11 pF Xc = 1593 I = 10607/1593 = 6.66 Arms -- Jeff WN3A
/archives//html/Amps/2012-08/msg00502.html (13,293 bytes)

9. Re: [Amps] Unique Henry Classic VHF console amps on QTH (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Tue, 12 Mar 2013 11:05:10 -0400
There was an article published (Handbook? QST? QEX?) for homebrewing a 2m kilowatt-class amp using the 3CX1200Z7/YU-181. I'm wondering how close the Henry design is to that. The Z7 is a nice tube fo
/archives//html/Amps/2013-03/msg00184.html (9,509 bytes)

10. Re: [Amps] Time for New Power Meter (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Mon, 04 May 2015 10:32:32 -0400
Yes, at VHF and above I use DC's and HP power meters and sensors (E4418/4419) to check the accuracy of other meters. HP (er, Keysight) has spreadsheets for calculating error/uncertainty given all of
/archives//html/Amps/2015-05/msg00052.html (11,225 bytes)

11. Re: [Amps] 3CX1500A7/8877 (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Mon, 13 Feb 2017 11:15:47 -0500
John, Were you on the design team for the BE transmitters of that era that started the "folded half-wave" cavity design, eliminating plate blockers? If so, kudos to you. I've had the pleasure (mostl
/archives//html/Amps/2017-02/msg00078.html (7,248 bytes)

12. Re: [Amps] SS amps watercooling - was PowerGenius XL (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Mon, 6 Mar 2017 13:32:07 -0500
I agree. In liquid-cooled broadcast transmitters (both tube and solid-state), the thermal transfer fluid is typically a 50/50 mix of distilled water and Dowtherm SR-1. SR-1 is ethylene glycol with c
/archives//html/Amps/2017-03/msg00052.html (11,931 bytes)

13. Re: [Amps] SS amps watercooling - was PowerGenius XL (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Tue, 7 Mar 2017 09:52:14 -0500
No, you have it backwards. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus _______________________________________________ Amps mailing list A
/archives//html/Amps/2017-03/msg00070.html (8,529 bytes)

14. Re: [Amps] 240 Volt Blowers needed (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Mon, 20 Mar 2017 17:36:07 -0400
Which is why if there is ever a chance that you might need both 120 and 240 in the same piece of equipment, run a 4-wire branch circuit (two hots, neutral, EGC) and use a 4-wire receptacle like a L1
/archives//html/Amps/2017-03/msg00119.html (9,524 bytes)

15. Re: [Amps] 240 Volt Blowers needed (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Mon, 20 Mar 2017 18:15:25 -0400
As I said, it is applicable to existing installations where the branch circuit doesn't have a separate EGC, but the appliance presents both 240V line-to-line and 120V line-to-neutral loads. It's not
/archives//html/Amps/2017-03/msg00121.html (9,355 bytes)

16. Re: [Amps] HV MOSFETs for RF (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Fri, 5 May 2017 14:17:54 -0400
Most definitely - just about any multi-carrier system. But let's separate "modulation modes" from the requirement that an *amplifier* be ideally linear. In the non-amateur world (including broadcast
/archives//html/Amps/2017-05/msg00073.html (9,022 bytes)

17. Re: [Amps] LDMOS availability (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Wed, 7 Jun 2017 12:21:00 -0400
Harris DX50 probably? But if it were a DX50, the design was such that the modules weren't operated separately for RF and modulation. The amplifier modules all ran at RF, and they were individually s
/archives//html/Amps/2017-06/msg00111.html (10,607 bytes)

18. Re: [Amps] Ten-Tec Titan 10 Meter Input SWR (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Sun, 11 Jun 2017 20:28:47 -0400
I think the above needs additional clarification. If there is a 2:1 load mismatch, and if the characteristic impedance (Z0) of the transmission line is the same as the Z the transmitter is designed
/archives//html/Amps/2017-06/msg00177.html (13,402 bytes)

19. Re: [Amps] Ten-Tec Titan 10 Meter Input SWR (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Mon, 12 Jun 2017 09:55:14 -0400
OIB's are quite handy. I have an OIB3 and always wanted an OIB2. You can also do high-power swept Z measurements using a conventional vector network analyzer (i.e. one without an integral test set)
/archives//html/Amps/2017-06/msg00185.html (9,546 bytes)

20. Re: [Amps] Thread size for UHF connectors? (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Wed, 7 Mar 2018 12:43:31 -0500
5/8-24 -- Jeff WN3A -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus _______________________________________________ Amps mailing list Amps@con
/archives//html/Amps/2018-03/msg00021.html (7,990 bytes)


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